Motor drive control apparatus

Abstract

A motor drive control apparatus for driving and controlling a linear vibration motor having a mover supported by a spring, with an AC current. The motor drive control apparatus includes a waveform creation unit for creating a comparative current waveform to be a reference of a driving current for the linear vibration motor based on the operating condition of the linear vibration motor, a current detector for detecting the driving current, and a controller for controlling a driving voltage of the linear vibration motor so that a difference between the comparative current waveform and a waveform of the current detected by the current detector becomes zero. The frequency of the driving current is controlled to be close to the resonance frequency of the linear vibration motor, based on the comparative current waveform. Accordingly, the driving frequency of the linear vibration motor can always be brought to the resonance frequency without using a sensor for detecting a displacement, speed, or acceleration of the mover, for example.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to a motor drive control apparatus and, more particularly, to a motor drive control apparatus for controlling a linear vibration motor on the basis of its driving current, thereby to drive the motor with high efficiency.BACKGROUND ART[0002]Conventionally, linear motors have been used as sources of reciprocating vibrations (refer to Japanese Published Patent Application No. Hei.2-52692 (FIG. 1)). This literature discloses a linear motor for generating a reciprocating vibration (hereinafter referred to as a linear vibration motor).[0003]The linear vibration motor is constructed as a single-phase sync motor having a mover comprising a rod-shaped permanent magnet, and a stator comprising an electromagnet. The electromagnet is obtained by winding a coil around both ends of a U-shaped iron core.[0004]An output voltage from an AC power supply is converted into a full-wave rectified voltage having a frequency twice as high ...

AI Technical Summary

Benefits of technology

[0028]Further, in the cryogenic freezer using the linear vibration motor of the present invention for the motor of the compressor, since friction loss in the compressor is reduced, the amount of waste oil (spent lubricating oil) and the amount of refrigerant to be filled in the compressor can be reduced as in the air compressor of the eighth aspect, resulting in a contribution to conservation of the global environment.

[0029]Further, in the cryogenic freezer of the present invention, the frequency of the AC current as the driving current of the linear vibration motor is determined so that the supply power to the linear vibration motor becomes maximum, under the state where the amplitude value of the AC current is maintained at the target amplitude value. Therefore, as in the air conditioner of the eight aspect, drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations in the compressor, without the necessity of incorporating a sensor, which undesirably leads to increases in size and cost of the compressor, and unnecessary restrictions such as securing operation reliability of a sensor.

[0030]According to an eleventh aspect of the present invention, a hot-water supply unit is provided that has first and second heat exchangers which form a circulation path for a refrigerant, and a compressor which has a cylinder and a piston, and circulates the refrigerant in the circulation path by reciprocating motions of the piston. The hot-water supply unit includes a linear vibration motor for making the piston reciprocate. The motor has a stator and a mover, which is supported with a spring so as to form a spring vibration system including the mover. The hot-water supply unit also includes a motor drive control unit for driving and controlling the linear vibration motor. The motor drive control unit is a motor drive control apparatus according to any one of the first to seventh aspects. Therefore, friction loss in the compressor is reduced as compared with a hot-water supply unit using a rotation-type motor as a motor of the compressor, and further, sealability for sealing the refrigerant in the compressor is enhanced, resulting in an increase in operation efficiency of the compressor.

[0031]Further, in the hot-water supply unit using the linear vibration motor of the present invention for the motor of the compressor, since friction loss in the compressor is reduced, the amount of waste oil (spent lubricating oil) and the amount of refrigerant to be filled in the compressor can be reduced as in the air compressor of the eighth aspect, resulting in a contribution to conservation of the global environment.

[0032]Further, in the hot-water supply unit of the present invention, the frequency of the AC current as the driving current of the linear vibration motor is determined so that the supply power to the linear vibration motor becomes maximum, under the state where the amplitude value of the AC current is maintained at the target amplitude value. Therefore, as in the air conditioner of the eight aspect, drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations in the compressor, without the necessity of incorporating a sensor, which undesirably leads to increases in size and cost of the compressor, and unnecessary restrictions such as securing operation reliability of the sensor.

[0033]According to a twelfth aspect of the present invention, a handy phone is provided that has a linear vibration motor for generating vibrations, and a motor drive control unit for driving and controlling the linear vibration motor. The linear vibration motor has a stator and a mover, which is supported by a spring so as to form a spring vibration system including the mover. The motor drive control unit is the motor drive control apparatus according to any one of the first to seventh aspects. Therefore, the process of detecting the resonance frequency of the linear vibration motor included in the handy phone can be carried out without using a position sensor for detecting the position of the mover or the like, whereby drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations in the compressor, without the necessity of incorporating a sensor, which undesirably leads to increases in size and cost of the compressor, and unnecessary restrictions such as securing operation reliability of the sensor.

Problems solved by technology

Thereby, drive control for driving the linear vibration motor can be realized with high efficiency regardless of load fluctuations, without the necessity of incorporating a sensor, which undesirably leads to an increase in size of the linear vibration motor, and unnecessary restrictions such as securing operation reliability of the sensor.

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